Litmus milk

This test is rarely used due to the length of time required, but references to it may be found in older literature. Litmus is added to milk until a pale purple colour is 

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Biochemical tests are usually performed after pure cultures have been obtained. The standard indole, methyl red, Voges-Proskauer, citrate, and litmus milk tests may be used to show important physiological characteristics. To study the functional diversity of bacteria, the utilization of carbohydrates, amines, amides, carboxylic acids, amino acids, polymers, and other carbon and nitrogen sources can be tested.28 Dilution-based most-probable number (MPN) techniques with phospholipid fatty acids as biomarkers have been employed for studying different bacterial species in lakes.40 The patterns of antibiotic resistance in bacteria isolated from natural waters have been useful for identifying sources of water pollution.34... 

The reports on radiation-resistant organisms on other sea foods include codfish (8), flounder, rockfish, and salmon (5), and haddock and clams (10). Liuzzo and co-workers (7) studied the morphology and metabolism of seven radiation-resistant bacteria isolated from fresh Gulf shrimp to ascertain if radiation altered their characteristics. They observed radiation-induced differences in optimum incubation temperature, chromogenesis, carbohydrate and vitamin utilization, and action on litmus milk (Tables V and VI). 

Tolerance o/Lactococcus lactis to High Concentrations of Nisin Prepare cultures of Lactococcus lactis (ATCC 11454, NCIMB 8586) in sterile skim milk by incubating for 18 h at 30°. Prepare one or more flasks containing 100 mL of litmus milk, and sterilize at 121° for 15 min. Suspend 0.1 g of sample in the sterilized litmus milk, and allow to stand at room temperature for 2 h. Add 0.1 mL of the L. lactis culture, and incubate at 30° for 24 h. L. lactis will grow in this concentration of sample (about 1000 IU/mL) however, it will not grow in similar concentrations of other antimicrobial substances. This test will not differentiate Nisin from subtilin. 

Kind of Bacteria in Steep-water. Out of 60 cultures inoculated into litmus milk 28% peptonized the casein. Of these 60 cultures examined 63 were spore-formers. 

Litmus milk changes from acid to alkaline. 

Litmus milk changes from alkaline to acid. 

Objective Characters.—Note is made if the milk has the normal pleasant taste and smell if it is bitter, add, soapy, salty (altered) if it has the normal opaque white colour and is not yellowish, reddish or bluish (altered). Its reaction to litmus paper should be amphoteric. 

Experiment 51. — Determine by the litmus test the nature of lemon juice, vinegar, soap, sweet and sour milk, washing soda, borax, wood ashes, faucet water, baking soda, sugar, cream of tartar, the juice of any ripe fruit and any green fruit. 

The blue dye lacca, which can be extracted from the lichens Roccella and Leca-nora with alkali and milk of lime, is the basis for the well-known litmus solution, which functions as an acid-base indicator in the pH range 4.4-8.0. The name litmus comes from the Dutch lackmoes (from moes = mush, paste). 

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